This invention relates to the field of flexible lightweight containers which provide a thermal barrier to maintain the initial temperature of the contents for an extended period of time. In the terminology of this application, the initial temperature of the contents refers to a temperature significantly above or below ambient temperature.
Thermos bottles and their vacuum properties are old and well known in the food arts for maintaining a particular internal temperature for a long time. Because of the concentric tubes separated by a partial vacuum, these bottles are usually used for storing liquids.
Larger containers, usually referred to as, xe2x80x9ccoolers,xe2x80x9d are used to store solid foods and bulkier items. These devices rely on the thick walls with low thermal conductivity to provide a thermal barrier. The wall structure is foam material having low heat transmission index covered on both sides with a hard plastic or metal for rigidity and support. In general, the coolers are not as efficient as the vacuum bottle since there is a greater transfer of heat across the wall structure of the cooler. Both the vacuum bottle and the cooler have an enclosed space surrounded by rigid walls making them both cumbersome and heavy to transport.
There are flexible thermal pouches in the food arts. Probably, most well known are the pouches used to deliver pizza pies. These devices also depend on a thick wall structure to provide a barrier to separate the thermal difference between the inside of the pouch and the outside, ambient, temperature. The wall structure of the pouches is similar to the coolers without the hard shell for support. Because of the thickness of the wall structure, the pouches occupy a great deal of space for the size of the interior.
In addition to the thermal devices discussed above, the food arts include thin plastic storage bags which protect the contents from the outside atmosphere. There are several different closures used to temporarily or permanently seal the bags. One type of temporary closure has a flexible bead that may be forced into a flexible groove to form a seal.
However, what is needed in the food art is a thin flexible re-sealable bag that has the thermal properties of a much bulkier thermal pouch or cooler.
There are several patents that teach the use of thin plastic bags for storage of food items. Among the patents are U.S. Pat. No. 5,582,853 directed to a display bag having a polyester outer layer, U.S. Pat. No. 5,941,641 directed to a polyester plastic bag with particular features of bag construction, U.S. Pat. No. 5,535,543 directed to a plastic bag having thermo-protection, and U.S. Pat. No. 5,674,010 teaching a bendable material for closing the mouth of the bag.
There are other bags with thermal properties, such as U.S. Pat. No. 6,007,245 to a infrared cloaking bag, for use by a human to evade IR sensors. These bags, in the nature of a sleeping bag, are laminated structures of a polyester and a metalized coating.
A thin, lightweight, flexible bag for enclosing contents with an initial temperature and maintaining the initial temperature of the contents for an extended period of time. The flexible bag has metalized polymer walls having opposite end edges and opposite side edges. The opposite end edges and opposite side edges superimposed the opposite end edges and opposite side edges forming a periphery having four sides. The periphery being integrally closed on three sides, a mouth formed on the fourth side. The mouth having a re-sealable friction fit closing device having cooperating components fixed to the opposite end edges. One of the cooperating components being an elongated bead, another of component being a channel shaped receiver. Whereby the bead is resiliently engaged with the receiver to temporarily close the bag.
Accordingly, it is an objective of the instant invention to teach a thin flexible bag having thermal properties.
It is a further objective of the instant invention to teach a thin flexible bag having laminated wall structure which provides strength and has a low thermal transmission.
It is yet another objective of the instant invention to teach a bag having polymeric walls laminated with a metalized coating and a temporary seal for the mouth of the bag.
It is a still further objective of the invention teach a laminated bag construction which provides secure seams and a sealed mouth that maintains the initial temperature of the contents for an extended period of time.
Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.